The term “product description” refers to information attached to a product. For example, the product description may include just the name of a product, such as “white bread”. Alternatively the product description may correspond to a product specification. Then it might include the following text: “white bread is made of wheat flour, water, yeast, and salt”. The product description may also include the following items of information: the brand name, the production date, the purchase date, the date of the end of validity, and/or the length of the validity period for the product.
The invention relates to the bar code technique and the RFID (Radio Frequency Identification) technique; thus these techniques are briefly discussed below.
The bar code technique is especially used in retail stores in which a cashier reads via a bar code reader the bar codes printed on products and a data system used by him/her fetches the prices related to the bar codes and prints the prices and the total sum on the receipt to be given to a customer.
The EAN-13 (European Article Number) bar code, whose 13 numbers specifies a product at a cash terminal, is widely used in Europe. Also a shorter EAN-8 bar code is used in some products. UPC coding, which is similar to the EAN coding, is used in North America. Both types of codes are termed unidimensional codes. There are also so-called two-dimensional codes that include a much greater amount of data compared to unidimensional codes.
The printing of bar codes does not increase significantly the production costs of a container. Therefore, in the future the bar code printed on a container will probably be used for disclosing not only a product code but also other items of information. These items of information may be, for example, the production lot/batch of a product or some other item of information making it easier to identify the product.
The RFID technique is utilized in a number of identifiers that are readable from a distance. In Europe the RFID systems usually use the following frequency bands: below 125 kHz, 13.56 MHz, 869 MHz, and 2.45 GHz.
RFID identifiers can be divided into two main classes: active identifiers and passive identifiers. An active identifier includes the power supply from which its transmitter obtains its energy. A passive identifier obtains its energy from the electromagnetic field. The reading distance for the active identifiers is at most several hundred meters. In contrast, the reading distance for the passive identifiers is at most four meters.
Simple passive RFID identifiers have been used in theft protection systems. For example, in clothes shops the identifiers intended for theft protection are attached to the clothes. Only one bit is required in these RFID identifiers, a bit disclosing whether the product has been paid for or not. If the storage capacity of ten bits is available, it is possible to store an integer number between 0 and 1023 in an RFID identifier. If there is even more storage capacity available, it is possible to store in the RFID identifier a product code, for example.
Compared to a bar code, an RFID identifier comprises the following benefits. For example, it is possible to read the RFID identifier through clothes. The reading of the RFID identifier does not require as precise an alignment for the reading device as the reading of a bar code. The maximum distance for reading the RFID code is greater than that for the bar code. In addition, the RFID identifier is readable even if its surface is dirty.
The invention relates to ways to help visually impaired persons in their everyday tasks. A task may be observing the content of a refrigerator, or observing the content of a food cupboard. A person having normal vision can, for example, read the date of the end of validity printed on a carton of milk, but a visually impaired person cannot do so without assistance. It is possible to store the date of the end of the validity in a bar code, but the use of a bar code reader is quite difficult for the visually impaired person even when the bar code reader announces with an audio signal that the reading of the bar code was successful.
If the bar code does not disclose the date of the end of validity, it is possible to determine on the basis of the purchase date whether the product is still valid or not. For example, yoghurt which was bought two months ago and has been forgotten in the refrigerator is probably spoilt. An RFID identifier would obtain from the storing means the date of the end of validity or for some other type of product description, but because of high prices of the RFID identifiers they are not yet attached to the products on sale in retail stores.
One drawback of the prior art techniques can be considered the fact that the visible impaired find it difficult or impossible to read product descriptions.
By means of the prior art, it is possible to fetch product information from a data communication network. For example, it is possible to fetch the price information of products. The publication U.S. Pat. No. 5,721,421 presents a method whereby a bar code of a product is read via a bar code reader and transformed into a product code having a binary form. In order to detect and fix possible data communication errors, a check code is added to the product code after which the product code is sent as a wireless signal to a terminal. Then the product code is sent from the terminal as a radio frequency signal to a server, and in response to this radio frequency signal the server sends the product price to the terminal.
This patent application is based on the applicant's earlier patent application FI20045404 filed in Oct. 26, 2004.